Aqueous dispersions of low-molecular weight, low-melting and water insoluble polymers

ABSTRACT

An aqueous dispersion of (a) 0.1-40% by wt. of a low molecular weight, low melting point, water-insoluble polymer in which the polymer particles have a size &lt;10 microns, and (b) 0.001-30% by wt. of an anionic emulsifier.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to aqueous dispersions of a low molecularweight, low melting point, water-insoluble polymer, and, moreparticularly, to a process of making such dispersions for use inwater-resistant compositions.

[0003] 2. Description of the Prior Art

[0004] The art has long recognized the need to provide aqueousdispersions of water-insoluble polymers which can be used inwater-resistant compositions such as seed coatings, water-basedprotective coatings, adhesive binders, water-based formulations forwater-proofing, suspension concentrates, sustained release formulations,water-based formulations for UV protection, agricultural formulationsand personal care products.

[0005] Accordingly, it is an object of this invention to provide aqueousdispersions of water-insoluble polymers.

[0006] Another object herein is to provide a process for making suchaqueous dispersions of water-insoluble polymers.

SUMMARY OF THE INVENTION

[0007] What is described herein is an aqueous dispersion of (a) 0.1-40%by wt. of a low molecular weight, low melting point, water-insolublepolymer in which the polymer particles have a size <10 microns, and (b)0.001-30% by wt. of an anionic emulsifier; preferably wherein (a) is5-30% and (b) is 2-20%; most preferably (a) is 10-20% and (b) is 5-10%.Suitably (a) is a vinyl pyrrolidone copolymer; preferably, (a) is avinyl pyrrolidone-alkylated or vinyl acetate copolymer.

[0008] In the aqueous dispersion of the invention, suitably (b) issodium lauryl sulfate, calcium dodecyl benzene sulfonate, tristyrylethoxylated phosphoric acid or salts thereof, polymeric anionicemulsifiers including lignin sulfonate, neutralized methyl vinyl ethermaleic acid half-ester, and polyacrylic acid with >10% acrylic acid, orsalts thereof.

[0009] In the aqueous dispersion herein (a) suitably, has a molecularweight <100,000, and a pyrrolidone content >10%.

[0010] As a feature of the invention, there is provided a process ofmaking the desired aqueous dispersion by heating the polymer and anionicemulsifier in water at a temperature close to the Tg of the polymerunder high shear mixing conditions, suitably at 40-90° C., preferably50-80° C., and, most preferably at 60-75° C., and wherein the polymerand anionic emulsifier are present in amounts of 1-40 wt. % and 0.001-30wt. %, respectively.

DETAILED DESCRIPTION OF THE INVENTION

[0011] In accordance with the invention, there is provided herein anaqueous dispersion of a water-insoluble polymer for use in variouscommercial applications and formulations. The dispersion is made hereinby an advantageous process in which the molten polymer is dispersed inan anionic emulsifier and water as a fine suspension. In the preferredembodiment of the invention, the water-insoluble polymer is heated toclose to its Tg, then water and the anionic emulsifier are heated andadded to the molten polymer while stirring vigorously under a highshear. The resultant dispersion of the polymer is a homogeneousmicro-dispersion in which the polymer particles have a size <10 microns,preferably 0.1-2μ.

[0012] The micro-dispersion thus prepared then can be added convenientlyto a particular formulation for use in a commercial application at asuitable dilution ranging from 1:10 to 1:1000.

[0013] Suitable water-insoluble polymers include, but are not limited,to the following:

[0014] Vinyl pyrrolidone copolymers like alkyl grafted PVP(Ganexo®/Agrimer® AL 30, 22, 25, WP 660) Agrimer® VA (PVP-vinyl acetatecopolymers).

[0015] Others: Beeswax and alkyl vinyl ether-maleic acid half-esterpolymers.

[0016] Preferred polymer molecular weight: <100,000, and pyrrolidonecontent >10%.

[0017] Suitable anionic emulsifiers include, but not limited to, lowmolecular weight sodium lauryl sulfate, calcium dodecyl benzenesulfonate, tristyryl ethoxylated phosphoric acid or salt; polymericanionic emulsifiers such as lignin sulfonate, preferably with amolecular weight >6000, methyl vinyl ether-maleic acid half-esterpartially neutralized; and water soluble polyacrylates with at least 10%acrylic acids/salts.

[0018] Suitable relative amounts of polymer and anionic emulsifier are:polymer 0.1-40%, preferred 5-30%, most preferred 10-20%, in water.Anionic emulsifiers or polymeric anionic emulsifiers: 0.001-30% byweight of the polymer to be dispersed, preferably 0.002-20%, mostpreferred 0.005-10%.

[0019] The temperature of heating is close to the glass transitiontemperature or molten/softening point, usually between 40-90° C.,preferably 50-80° C., most preferably 60-75° C.; and under high shearmixing.

[0020] The following examples describe the invention more particularly:

[0021] Examples 1 through 18 illustrate the preparation of fine, aqueousdispersions of water-insoluble polymers such as Agrimer® AL(alkyl-grafted polyvinyl pyrrolidone copolymers) with anionicemulsifiers, and uses of such dispersions.

EXAMPLE 1

[0022] A solid version of Ganex® 516 or Agrimer® AL 25 (vinylpyrrolidone grafted with 50% C₁₆ alpha-olefin) was prepared from acommercially available 50% solution of the polymer in isopropanol. 500 gof the commercial 50% IPA solution then was charged into a 1-I,three-necked round-bottom flask equipped with a thermometer, a refluxcondenser and a mechanical stirrer. The solvent was stripped undervacuum (2-5 mm Hg) at a temperature below 50° C. After 70-80% IPA wasremoved, about 400 g water was introduced and the remaining IPA wasazeotroped off leaving a thick suspension of the polymer in water. Aportion (about 100 g) of the thick suspension (Composition 1A)containing about 60% solid was used to prepare an aqueous dispersion.The remaining portion was transferred to a vacuum oven and water wasremoved at 1-2 mm Hg pressure and <60° C. over a period of 24 hours. Thesolid produced was ground in an electrical grinder to produce aquantitative amount of free-flowing solid (Composition 2A).

EXAMPLE 2

[0023] 8.5 g of Composition 1A of Example 1 was diluted with 50 g waterin a 250 ml beaker. 0.66 g of an emulsifier, sodium laurylether-2-sulfate was added. The mixture was agitated with a magneticstirrer, and the composition was further diluted to a total weight of100 g. The product was transferred into a 2 oz. stoppered bottle andstored in an oven maintained at a temperature of about 50° C. for aperiod of 24 hours.

[0024] A stable slightly hazy dispersion was produced. The dispersionremained without separation at room temperature for a period of onemonth. This dispersion was suitable for coating many substrates, likewood, skin, seeds, and granules, to provide rainfastness or protectionagainst water as well as to keep the hydrophobic bioactive materialssuspended in solution.

EXAMPLE 3

[0025] 5 g of Composition 2A was suspended in 0.43 g of sodium laurylether-2-sulfate in a 2 oz. stopperd bottle and the sample was made up to100 g with water. The sample was stored in an oven maintained at atemperature of about 50° C. for a period of 24 hours. A stable, hazydispersion was produced. The dispersion remained without separation atroom temperature, observed for a period of one month.

EXAMPLE 4

[0026] 3 g Agrimer® AL 30 (vinyl pyrrolidone alpha-olefin graftcopolymer produced with 20% vinyl pyrrolidone and 80% C₂₀ alpha-olefin)was weighed into a one oz. stoppered bottle and suspended in 11.85 gwater containing 0.15 g Reax 85A (lignin sulfonate with molecularweight˜10,000). The suspension was kept in an air-oven at 75° C. for 6hours. The contents were mixed occasionally, removed from the oven andstored at room temperature. The product was a homogeneous dispersionwith a polymer particle size <5 microns.

EXAMPLE 5

[0027] Example 4 was repeated except that 0.15 g lignin sulfonate wasreplaced by 0.15 g Soprophor 3 D 33 (tristyryl phenyl ethoxylatedphosphoric acid). The polymer formed a homogeneous dispersion with aparticle size <5 microns.

Example 5A

[0028] Example 5 was repeated except that Agrimer® AL 30 was replaced byAgrimer® WP 660 or Ganex® WP 660. A homogeneous, stable dispersion wasproduced.

EXAMPLE 6

[0029] Example 4 was repeated except 0.15 g lignin sulfonate wasreplaced by 0.20 g Geropon SS 075, in an amount of 75%. A homogeneousdispersion with particle size <5 microns was obtained.

EXAMPLE 7

[0030] Example 4 was repeated except that 0.15 g of lignin sulfonate wasreplaced by 0.25 g Ninate 401 A, 60% (calcium dodecylbenzene sulfonate).The polymer formed a homogeneous dispersion with a particle size <5microns.

Example 7A

[0031] Example 7 was repeated except that the polymer was replaced withbeeswax and the emulsifier was 1:1 mixture of Igepal CO 630 and Ninate401 A. A stable dispersion was produced.

EXAMPLE 8

[0032] Example 4 was repeated except that 0.15 g lignin sulfonate wasreplaced with 0.15 g Soprophor 3 D 33 (tristyryl phenyl ethoxylatedphosphoric acid). The polymer formed a homogeneous dispersion with aparticle size <5 microns.

EXAMPLE 9

[0033] Example 7 was repeated except that 0.5 g Ninate 401 A, 60%(calcium dodecylbenzene sulfonate) was used. The polymer formed ahomogeneous dispersion with a particle size <5 microns.

EXAMPLE 10

[0034] 5.72 g Reax 85 A was dissolved in 237 g water in a 1-I beaker.The solution was placed in a Waring blender jar and placed in the ovenat 75° C. In a separate capped bottle, 57.15 g Agrimer AL 30 was placedin the oven at 75° C. After 3 hours, the Waring blender jar with theReax 85 A* (lignin sulfonate) was placed in the Waring blender. Themolten Agrimer AL 30 then was poured into the Reax 85 A. That solutionat 75° C. was sheared for 30 min. at maximum speed. The resultingsuspension was stable and produced a particle size distribution withless than one micron mean diameter. The suspension was stable for 24hours without separation; and was a non-settling, uniform dispersioneven after 4 weeks.

EXAMPLE 11

[0035] Example 10 was repeated on a smaller scale, using other ligninsulfonates in the place of Reax 85 A. 2.0 g of the following ligninsulfonates were dissolved in 78 g water in separate jars and kept in anoven at 75° C. 20 g Agrimer AL 30 was melted in 7 separate cappedbottles. Small scale Waring blender cups and jars were kept at 75° C.The molten Agrimer AL 30 was mixed in the blender with the hot ligninsulfonate solutions at high shear for 5 min.

[0036] The lignin sulfonates were:

[0037] Reax 85 A (Mol wt 10,000, sulfonation index 0.8, salt content4.8%);

[0038] Polyfon H (Mol wt 4300, sulfonation index 0.7, salt content 4%);

[0039] Polyfon T (Mol wt 2900, sulfonation index 2.0, salt content8.6%);

[0040] Polyfon O (Mol wt 2400, sulfonation index 1.2, salt content 5%);

[0041] Polyfon F (Mol wt 2900, sulfonation index 3.3, salt content12.7%);

[0042] Reax 88B (Mol wt 3100, sulfonation index 2.9, salt content 8.6%);

[0043] Reax 100 M (Mol wt 2000 sulfonation index 3.4, salt content6.5%);

[0044] Reax 825 E (Mol wt 3700, sulfonation index 3.4, salt content5.4%).

[0045] The quality of suspensions were good but Reax 85 A was better.

EXAMPLE 12

[0046] 1.9 g of 25% aqueous solution of disperse (commercial sample 5120[26.5% solid], pilot plant sample, with 27% esterification, Et/Bu at2.0,) was dissolved/diluted in 93.1 g water in a capped bottle and waskept in an oven at 75° C. 5.0 g Agrimer AL 30 was melted in a separatecapped bottle in an oven at 75° C. Small scale Waring blender cups andjars were kept at 75° C. The molten Agrimer AL 30 was mixed in theblender with the hot disperse solution with high shear for 5 min. A finedispersion of Agrimer AL 30 in water with bimodal particle sizedistribution with 90% particle size less than 6 microns (volume meandiameter) was produced.

EXAMPLE 13 Agrimer® AL 22 Suspensions

[0047] 3.8 g of 25% aqueous solution of disperse (commercial sample5120, pilot plant sample, with 27% esterification, Et/Bu at 2.0,) wasdissolved/diluted in 86.2 g water in a capped bottle and was kept in anoven at 75° C. 10.0 g Agrimer AL 22 was placed in a separate cappedbottle in an oven at 75° C. Small scale Waring blender cups and jarswere kept at 75° C. The liquid Agrimer AL 22 was mixed in the blenderwith the hot disperse solution with high shear for 5 min. A finedispersion of Agrimer AL 22 in water with slight bimodal particle sizedistribution with 90% particle size less than 3 microns (volume meandiameter) was produced.

EXAMPLE 14 Agrimer® AL 25 Suspensions

[0048] 3.8 g of 25% aqueous solution of disperse (commercial sample5120, pilot plant sample, with 27% esterification, Et/Bu at 2.0,) wasdissolved/diluted in 86.2 g water in a capped bottle and was placed inan oven at 75° C. 10.0 g solid Agrimer AL 25 (composition 2A describedin Example 1) was melted in a separate capped bottle in an oven at 75°C. Small scale Waring blender cups and jars were kept at 75° C. Themolten Agrimer AL 25 was mixed in the blender with the hot dispersesolution with high shear for 5 min. A fine viscous dispersion of AgrimerAL 25 in water with particle size distribution with 90% particle sizeless than 3 microns (volume mean diameter) was produced.

EXAMPLE 15 Agrimer® VA 5 Suspensions

[0049] 7.5 g of 25% aqueous solution of disperse (commercial sample5120, pilot plant sample, with 27% esterification, Et/Bu at 2.0,) wasdissolved/diluted in 72.5 g water in a capped bottle and was placed inan oven at 75° C. 40 g commercially available 50% ethanolic solution ofAgrimer VA 5 was placed in a separate capped bottle in an oven at 45° C.Small scale Waring blender cups and jars were kept at 75° C. The hotsolution of Agrimer VA 5 was mixed in the blender with the hot dispersesolution with high shear for 5 min. A fine clear yellow suspension ofAgrimer VA 5 in water with particle size distribution with 90% particlesize less than 4 microns (volume mean diameter) was produced. Thesuspension was analyzed to contain less than 10% residual ethanol. Theresidual ethanol was removed to <0.5% by flushing dry nitrogen for aperiod of 24 hours.

EXAMPLE 16

[0050] 22.6 g of 26.5% aqueous solution of disperse (commercial sample5120 [26.5% solid], pilot plant sample, with 27% esterification, Et/Buat 2.0 was dissolved/diluted in 217.4 g water in a Waring blender jarand was kept in an oven at 75° C. 60.0 g Agrimer AL 30 was melted in aseparate capped bottle in an oven at 75° C. for a period of 3 hours.Molten Agrimer AL 30 was poured into the aqueous disperse at 75° C. andmixed with high shear for 5 min. The suspension was foamy. At thispoint, 0.2 g Rhodofac D 425 antifoam was added. Suspension continued tothicken. After 10 min. of shear, the thick suspension was poured hot ina labeled bottle. The last amount of the suspension was removed by aspatula. After cooling to room temperature, the suspension became a softsolid that will not pour, the solid polymer/dispersant imbibing morethan three times it's weight of water.

[0051] The concentrated 20% Agrimer AL 30 suspension described abovecould be easily diluted in water and shear-mixed to produce stable freeflowing dispersions containing desired amount of solids (10% or less).

[0052] Following dilutions were prepared to produce free flowing lowviscous aqueous suspensions.

Example 16A

[0053] One part (1 g) of suspension of Example 16 was diluted with twoparts of water (2 g) and mixed and vortexed to produce a fine suspensioncontaining 6.67% Agrimer AL 30 with submicron particle sizedistribution.

Example 16B

[0054] One part (1 g) of suspension of Example 16 was diluted with twoparts of water (3 g) and mixed and vortexed to produce a fine suspensioncontaining 5.0% Agrimer AL 30 with submicron particle sizeddistribution.

Example 16C

[0055] One part (1 g) of suspension of Example 16 was diluted with twoparts of water (4 g) and mixed and vortexed to produce a fine suspensioncontaining 4.0% Agrimer AL 30 with submicron particle sizeddistribution.

Example 16D

[0056] One part (1 g) of suspension of Example 16 was diluted with twoparts of water (9 g) and mixed and vortexed to produce a fine suspensioncontaining 2.0% Agrimer AL 30 with submicron particle sizeddistribution.

EXAMPLE 17

[0057] Use of polymer dispersions for rainfastness. Meltaldehydesuspension concentrates.

[0058] Following suspension concentrates [17A, 17B, 17C and 17D]containing 25% Metaldehyde were prepared using the general proceduredescribed below: TABLE 1 17B 17C 17D 17A Reax 85A/ disperse/ disperse/Commercial slug Formulations/ dISPerse/ Agrimer 30/ Agrimer AL 30/Agrimer 30/ fast (oil based Ingredients Agrimer 30 Agrimer AL 30 Reax85A Agrimer AL 30 suspension) Metaldehyde 25.1 25.1 25.1 25.1 25%Disperse 5120 2.0 2.0 2.0 2.0 (26.5% solid) Agrimer 30 2.6 2.6 0 2.6Reax 85 0 15.1 15.1 0 A/Agrimer AL 30, 19%¹ DISPerse/Agrimer 0 0 0 15.1AL 30, 20%² Propylene glycol 3.51 3.51 3.51 3.51 Rhodasil 0.2 0.2 0.20.2 Proxel 0.25 0.25 0.25 0.25 Kelzan (1% in 15.1 15.1 15.1 15.1 Water)Water added 51.24 36.14 38.74 36.14 Total 100.00 100.00 100.00 100.00

[0059] Preparation. The suspension concentrate compositions shown in17A, 17B, 17C and 17D (excluding the 1% Kelzan), were wet-milled usingan Eiger Machinery Model #100 before testing. Prior to feeding into thewet mill they were mixed using a homogenizer. Typically, a 70% to 80%loading of 0.1 cm zirconium oxide beads was used and concentrates weremilled for 10 minutes at 3000 rpm. The temperature of the cooling bathwas typically −5° C. to 0° C., which gave a milling temperature between15° C. and 21° C. for the concentrates. The operating conditions of thewet-mill resulted in about 19 passes of the concentrate per minute. 15.1g 1% Kelzan solution was added to 94.9 of the wet-milled concentratesprepared as above.

[0060] The above formulations produced fine suspensions with particlesize distribution, at 90% less than 2.5 microns, with mean volumediameter less than 1.5 microns.

Applications

[0061] Rainfastness Evaluation

[0062] The formulations 17A, 17B, 17C, 17D and commercial slug fast wereevaluated for rainfastness as follows:

[0063] The formulations were diluted at 1:60 with deionized water andthe Metaldehyde was well suspended. Glass microscopic slides (1×4 inch)were dipped half way into the diluted suspensions and were air-dried.After drying 5 mL water was poured over one side on the slides from agraduated pipette, slides were dried again and were examined under themicroscope to assess the extent of adhesion or wash off of theMetaldehyde crystals.

[0064] The Metaldehyde from the commercial Slugfast formulation wascompletely washed off. Formulation 17D retained >95% of the originalsolids on the slide. Formulations 17A, 17B and 17C retained 75-85% ofthe original solids.

EXAMPLE 18 Use of Disperse/Agrimer® AL 30/Agrimer® 30 in Seed Coating

[0065] A suspension concentrate composition shown below, containing 41%chlorothalonil suspension, was prepared by the procedure described inExample 17. Xanthan was added after milling to give a final xanthanconcentration of 0.16%. Ingredient Composition, % Chlorothalonil 41.0Disperse (25% solution) 2.0 Agrimer 30 2.6 Disperse/Agrimer AL 30 (20%)²15.1 2-ethylhexylsulfate 1.0 Propylene glycol 4.2 Proxel GXL 0.44Rhodorsil 426R 0.44 Xanthan 0.16 Water Qs to 100.00

[0066] One part of the above suspension was diluted with 2 parts of anaqueous solution containing 20% Chromakote Blue dye. 750 grams ofsoybean seeds (size 2760 seed per lb.) were charged into the Hege 11Liquid Seed Treater. 3 mls of diluted Formulation (as above) was appliedto the seeds, which were then allowed to dry on a glass tray for 30 min.

[0067] Adhesivity: Three 250 g portions of the treated seed were eachplaced on 10 mesh round sieve (8 in. dia., full height). The threesieves were stacked on a CSC Scientific Sieve Shaker, Model #18480, andwere shaken for 15 minutes at setting #7. The weight of the dustproduced from shaking the treated seeds was 40mg (ca: a retention >85%).

[0068] A formulation similar to the above, but without disperse/AgrimerAL 30 produced 120 mg dust in the Adhesivity test.

[0069] A. Other Applications:

[0070] The compositions shown in Examples 10 and 12-16, are effectivefor formulating personal care products including water-based UVprotectants, such as sunscreen and alpha hydroxy acid formulations, andwith film-forming water proofing polymers.

[0071] B. Sustained Release Formulations

[0072] The compositions shown above also are effective for formulatingsustained release alpha-hydroxy acids (lactic acid/glycolic acid), e.g.in the presence of Agrimer AL 30 and dISPerse.

[0073] While the invention has been described with particular referenceto certain embodiments thereof, it will be understood that changes andmodifications may be made which are within the skill of the art.Accordingly, it is intended to be bound only by the following claims, inwhich:

What is claimed is:
 1. An aqueous dispersion of (a) 0.1-40% by wt. of alow molecular weight, low melting point, water-insoluble polymer inwhich the polymer particles have a size <10 microns, and (b) 0.001-30%by wt. of an anionic emulsifier.
 2. An aqueous dispersion according toclaim 1 wherein (a) is 5-30% and (b) is 0.002-20%.
 3. An aqueousdispersion according to claim 1 wherein (a) is 10-20% and (b) is0.005-10%.
 4. An aqueous dispersion according to claim 1 wherein (a) isa vinyl pyrrolidone copolymer.
 5. An aqueous dispersion according toclaim 4 wherein (a) is a vinyl pyrrolidone-alkylated or vinyl acetatecopolymer.
 6. An aqueous dispersion according to claim 1 wherein (b) issodium lauryl sulfate, calcium dodecyl benzene sulfonate, tristyrylethoxylated phosphoric acid, or salts thereof, polymeric anionicemulsifiers including lignin sulfonate, neutralized methyl vinyl ethermaleic acid half-ester, and polyacrylic acid with >10% acrylic acid, orsalts thereof, and mixtures of the above.
 7. An aqueous dispersionaccording to claim 1 wherein (a) has a molecular weight <100,000 and apyrrolidone content >10%.
 8. A process of making the aqueous dispersionof claim 1 which comprises heating said polymer and anionic emulsifierin water at a temperature close to the Tg of the polymer under highshear mixing conditions.
 9. A process according to claim 8 wherein saidtemperature is 40-90° C.
 10. A process according to claim 9 wherein saidtemperature is 50-80° C.
 11. A process according to claim 9 wherein saidtemperature is 60-75° C.
 12. A process according to claim 8 wherein saidpolymer and anionic emulsifier is present in amounts of 1-40 wt. % and0.001-30 wt. %, respectively.
 13. A water-resistant compositionincluding the aqueous dispersion of claim
 1. 14. A water-resistantcomposition according to claim 13 which includes said dispersion at adilution of 1:10 to 1:1000.